The field of the present invention is conveying systems wherein the conveyor is actively operative to off-load products from the conveying surface.
Product handling activities for the discrimination of product units have long been used, particularly in the food product industry. Such discrimination has been based on size, ripeness, color, blemishes and the like. Until recent times, this activity was generally undertaken by manual labor. The versatility of workers for handling and processing large amounts and varieties of food products has generally been unsurpassed. Such processing systems generally include conveyor passing working stations where workers were able to distinguish and separate product units. Such labor was generally inexpensive and seasonal. However, difficulties in finding experienced seasonal workers and the normal administrative problems associated with the fluctuating work force have long created a need for less labor intensive systems.
In defining the needs for product handling systems, as particularly applied to the food industry, the nature, volume, relative unit cost and variety of products severely inhibit the design of handling equipment. Most food products must be handled with great care to avoid damage. The perishable nature and large batch quantities of products in season makes rapid processing a necessity. The variety of products which must be processed at different times to economically justify a food processing facility places great demand for versatility on the equipment. Thus, a substantial challenge exists in creating handling equipment to replace the versatile human worker.
Recently, high speed electronics and sophisticated software have provided increasing sensing capability for detecting size and condition of individual product units and rapidly activating responsive mechanisms to proceed to handle such products. However, such systems require a more exacting placement of the product units, a separation of product units, proper orientation and reorientation of product units and means for quickly but gently separating units one from another. The demands for such exacting placement, control and operation are orders of magnitude more stringent than for manual processing. Thus, the design of handling systems has resulted in compromises in speed, efficiency and product treatment.
An earlier system for handling of products in a manner acceptable for automatic sorting is disclosed in U.S. Pat. No. 4,106,628 to Warkentin et al. for SORTER FOR FRUIT AND THE LIKE, the disclosure of which is incorporated herein by reference. In this patented device, cups are arranged on a chain conveyor for holding individual product units. Solenoids act to dump selected cups for product separation responsive to discriminating sensing and electronic commands. Other separating systems include devices for batting or blowing selected units from a conveyor.
Another system which has been in use for some time is disclosed in U.S. Pat. No. 4,961,489 to Warkentin for PRODUCT HANDLING SYSTEM, the disclosure of which is incorporated herein by reference. In this device, a conveyor is employed which includes elements capable of tipping to off-load individual units of a product being processed. The nature of the conveyor permits some variety in shapes and sizes, including elongated products. However, a range of round or oval products in smaller sizes is not as easily accommodated by this system.
Another system which has been in use successfully for some time is disclosed in U.S. Pat. No. 5,029,692 to Warkentin for OFF-LOADING CONVEYING SYSTEM, the disclosure of which is incorporated herein by reference. In this device, a conveyor is employed which includes concave rollers defining concavities therebetween. Off-loading elements are positioned between adjacent rollers in each of the concavities. The elements are pivotally mounted about pivot axes parallel to the conveying direction and can be actuated to off-load product units away from these pivot axes.
A system used with such conveyors for discriminating product units is disclosed in U.S. patent application No. 479,107, now U.S. Pat. No. 5,156,278, filed Feb. 13, 1990, to Warkentin et al. for PRODUCT DISCRIMINATION SYSTEM AND METHOD THEREFOR, the disclosure of which is incorporated herein by reference. A fiber optic system is used to sense physical attributes of the conveyed product units. A system for rotating the fruit between sensors provided added accuracy.